I bought it and also bought an Aquaclear 20 immediately to replace the filter.

Since then, however, I purchased a separate 5.5 gallon as a quarantine tank and put the topfin filter on it. I ditched the filter media that came with it; instead I'm using a piece of Fluval sponge, and some biomass in mesh bags that came from two different cycled tanks. I think the theory was good, but unfortunately, the QT isn't cycled.

The filter itself is fine -- quieter than I thought it would be. It's larger than the Aquaclear 20 though.

I bought it and also bought an Aquaclear 20 immediately to replace the filter.

Since then, however, I purchased a separate 5.5 gallon as a quarantine tank and put the topfin filter on it. I ditched the filter media that came with it; instead I'm using a piece of Fluval sponge, and some biomass in mesh bags that came from two different cycled tanks. I think the theory was good, but unfortunately, the QT isn't cycled.

The filter itself is fine -- quieter than I thought it would be. It's larger than the Aquaclear 20 though.

Aquaclear is what i use for my 2 10 gallons. The top fin filter has no adjustable flow. I could tweek it but really am too lazy lol and rather just buy one that i know will work.

Do you think the aquaclear will work just as good and gentle in a 5.5 gallon as it does in a 10 gallon?

I think I will save the filter for a future 10 gallon tank. I will get the aquaclear and just replace the carbon with more sponge for the BB. Another trip to petsmart. I rather go to petco but i have a store credit at petsmart. :/

hey! i have this tank - purchased it approx 2months ago. looks great, gives the betta lots of room to swim and for decorations and plants... i have kept the original filter and light that comes with it - haven't had any issues with it so far. the only thing is i inserted a small piece of sponge into the intake for the filter to slow down the water flow as it was a bit too fast/strong for my betta. that really helped alot, it still keeps the aquarium clean but did slow down the water flow.

I got the aquaclear! and it works awesome on the 5.5 gallon. I replaced the carbon with an extra sponge for more BB! I'll save the top fin filter for another tank. Maybe. I like to stick with the things i like and trust. Not a big fan of top fin anymore.

i do! i bought some filter sponges and made a baffle for mine. i had a baby betta and she has had no problem swimming. this is what mine looks like now (see attachment)
all i use is a rubber band and a cut filter sponge. it can be easily removed for cleaning and it hasnt bothered my betta at all.